If you have noticed the audio of some agencies is not as loud
as it used to be on your scanner, this is an indication that the agency has
complied with the FCC mandate to upgrade to narrow band equipment. All
land mobile radio services above 150 mhz are required to complete transition to
narrow band equipment by Jan 1, 2013. Narrow band means the transmitted
audio bandwidth is reduced from 5 khz to 2.5 khz. This results in low
receive audio of "wideband" receivers that were designed for 5 khz. Narrow
band also has a reduction in the coverage area so you may not hear stations as
far away as you used to.